I'm F'in' confused!
Just want to know - what does the "F" stand for - seems like the generation from context.

Thanks! :D

I'm F'in' confused!
Just want to know - what does the "F" stand for - seems like the generation from context.

Thanks! :D

Sorry Heather, wish I knew :Grin:

I'm curious too though

I don't know the answer because I know nothing about slipper breeding but I do have F1, F2 and F3 on my keyboard. :lol: :lol: :Grin:

F#s are filial generations produced from a parental (p) generation. F1 is the first generation, F2 the second generation, etc.

If you were to make a hybrid cross using two parents, for example, P. micranthum x P. rothschildianum, these would be your p generation plants and the resultant first generation would be your F1s. F2 would be the progeny of self-pollinated F1 generation plants (or sibbed F1 generation plants).

Okay, great. That's what I figured from the context, but I wanted to be sure. Thank you!

it is the same thing with the frogs i have and most other animals

it is the same thing with the frogs i have and most other animals

All other animals... Anything that reproduces sexually. It is standard notation for genetics. Not used for humans for cultural reasons.

As to why F2 generations tend to display greater diversity in color and form:

Take for example, two P. rothschildianums of independent breeding, call them 'A' and 'B'
Each of the plants should have a chromosome number of 2n=26 (http://ladyslipper.com/pproth.htm)
The 26 chromosomes in each cell (that are the genetic makeup of the organism) in each plant are arranged in the nuclei into 13 numbered pairs, with each pair having a distinct length and shape.
When 'A' and 'B' are bred, each seed that is produced will get 13 chromosomes from each parent, 1 each (chosen at random) from the 13 numbered pairs. The 13 chromosomes from one parent automatically pair up with the 13 from the other parent to form the genetic makeup of the new seed.
This creates the F1 generation, which we can call 'A x B'.
The number of different offspring (containing at least a single different chromosome) that can be produced from this cross is 2^26 (2 x 2 x 2....26 times total), or 67,108,864. Each of the numbered chromosomes of each seed is chosen at random from the numbered pair of each parent, so the odds of a certain chromosome being passed on to an offspring is 1 in 2.

When siblings of the F1 generation are bred, the same process occurs as above, creating the F2 generation, which we can call '(A x B) x (A x B)'.
Now each chromosome in each chromosome pair among the F2's set of 26 could have come from either grandparent, 'A' or 'B'. Therefore, the number of different F2 offspring that can be produced is 4^26, or 4,503,599,627,370,496.
That is to say, each child of 'A' and 'B' must be chosen from among ~67 million possibilities, whereas each grandchild from a sib cross must be chosen from among ~4,500 trillion possibilities.
The greater number of possibilities leads to a greater diversity in color and form.

It is important to remember that during reproduction, which of each pair will be passed on by each parent is chosen at random.

Next installment: F3 generations and/or selfings and/or the role of plastid and mitochondrial DNA in determining color and form

--Stephen

As to why F2 generations tend to display greater diversity in color and form:

...
When 'A' and 'B' are bred, each seed that is produced will get 13 chromosomes from each parent, 1 each (chosen at random) from the 13 numbered pairs. The 13 chromosomes from one parent automatically pair up with the 13 from the other parent to form the genetic makeup of the new seed.
This creates the F1 generation, which we can call 'A x B'.
The number of different offspring (containing at least a single different chromosome) that can be produced from this cross is 2^26 (2 x 2 x 2....26 times total), or 67,108,864. Each of the numbered chromosomes of each seed is chosen at random from the numbered pair of each parent, so the odds of a certain chromosome being passed on to an offspring is 1 in 2.

When siblings of the F1 generation are bred, the same process occurs as above, creating the F2 generation, which we can call '(A x B) x (A x B)'.
Now each chromosome in each chromosome pair among the F2's set of 26 could have come from either grandparent, 'A' or 'B'. Therefore, the number of different F2 offspring that can be produced is 4^26, or 4,503,599,627,370,496.
That is to say, each child of 'A' and 'B' must be chosen from among ~67 million possibilities, whereas each grandchild from a sib cross must be chosen from among ~4,500 trillion possibilities.
...



And that doesn't even count recombination, where parts of paired chromosomes can swap around. This is a very important process in genetic diversity, and it happens a lot. A whole lot... In fact, we rely on that process (or used to rely on it, before genomes were sequenced) to tell us where genes are located on the chromosomes (don't ask me how). We use it so much that we have a unit of distance to describe how far apart genes are on a chromosome, called the centimorgan. That doesn't measure actual distance so much as the frequency of potential recombination events that can occur in the space between two genes.

So, not only do the chromosomes segregate independently, but individual genes segregate independently as well. Ain't genetics neat?